Re: [boost] [function types] New tag type logic [update]

From: Tobias Schwinger (tschwinger_at_[hidden])
Date: 2005-07-07 07:31:17

Paul Mensonides wrote:
>>In more detail: Given a compiler allows CV-qualified 
>>functions, these types pass 
>>the library without problems; the library detects them 
>>properly because top-level 
>>cv-qulification is ignored.
> 
> 
> I'm not sure what you mean here, but it makes me wary.  

The library uses the TypeTraits template 'remove_cv'. I

n theory e.g:

   template<typename T> struct remove_const          { typedef T type; };
   template<typename T> struct remove_const<T const> { typedef T type; };

should work, shouldn't it? In practice it depends on the compiler, of course.

> 
>>There is no way to emphasize a 
>>query or specification 
>>for the cv-qualification of nonmember callable builtin types, 
>>which would involve 
>>adding overhead for an esoteric and unportable feature.
> 
> 
> I assume that you mean compile-time overhead.  

What else could I possibly mean here?

> If you have support for pointers
> to cv-qualified member functions, it seems (to me) that the required boilerplate
> to deal with cv-qualified function types is already there.  If you don't have
> support for cv-qualified member functions, then you should; they are not
> esoteric at all.

Sure I have (btw. it would've not passed the review without, I guess) - but only 
for the function types in member function pointers. Implementing things 
differently would mean a lot of portability-trouble.

> 
> The only reason for library support for them (cv-qualified function types), IMO,
> is completeness.  I'm not saying that it is particularly useful.
> 

In a perfect world (where your "remove_member_pointer" template always works) I'ld 
support them. However, currently I don't see that completeness outweighs its price 
here. Further I believe it's a good idea to keep the user away from dark corners 
of the language by design.

Regards,

Tobias